The invention relates to a device for the manufacture or repair of a three-dimensional object in accordance with the present invention. The invention further relates to a suction nozzle and an inlet nozzle for use in a device for the additive manufacture or repair of a three-dimensional object also in accordance with the present invention.
Methods and devices for the manufacture of three-dimensional objects, in particular components, are known in great variety. In particular, additive manufacturing methods (so-called rapid manufacturing or rapid prototyping methods) are known, in which the three-dimensional object or the component is built up layer by layer by means of additive manufacturing methods based on powder beds. Primarily metal components can be manufactured by laser or electron-beam melting or sintering methods, for example. In these processes, at least one powdered component material is deposited initially layer by layer on a component platform in the region of a buildup or joining zone of the device. Subsequently, the component material is locally melted and/or sintered layer by layer by supplying at least one high-energy beam, such as an electron or laser beam, for example, to the component material in the region of the buildup and joining zone. In the process, the control of the high-energy beam depends on information about the layer of each of the component layers being manufactured. After the melting and/or sintering, the component platform is lowered layer by layer by a predefined layer thickness. Afterward, the steps mentioned are repeated until final complete fabrication of the component has occurred. Comparable additive methods are known for the manufacture of ceramic or plastic elements.
Also known from prior art are, in particular, additive manufacturing methods for the manufacture of components of a turbomachine, such as, for example, components of an aircraft engine or a gas turbine—for example, the method described in DE 10 2009 051 479 A1 or a corresponding device for the manufacture of a component of a turbomachine. In this method, a corresponding component is manufactured by deposition of at least one powdered component material layer by layer on a component platform in the region of a buildup and joining zone as well as local melting or sintering of the component material layer by layer through energy supplied in the region of the buildup and joining zone. The energy is supplied in this case via laser beams, such as, for example CO2 lasers, Nd:YAG lasers, Yb fiber lasers as well as diode lasers, or else by electron beams.
The removal of process by-products is usually implemented in the generic devices and methods by a flow of protective gas, which is generally passed over the entire mentioned component platform or a buildup and joining zone. In this case, known devices for the additive fabrication of three-dimensional objects comprise a plurality of inlet nozzles for the protective gas as well as at least one suction nozzle. Used in particular are inlet nozzles that, on the one hand, are arranged laterally above the buildup and joining zone and, on the other hand, are arranged in an upper region of the device that lies opposite the buildup and joining zone. Owing to its geometry and position, the latter-mentioned upper inlet nozzle has a direct influence on the volume flow and the flow field of the flow of protective gas in the construction space or the process chamber above the component platform. In this case, the centered arrangement of the upper inlet nozzle in the upper region of the device can lead to an inhomogeneous flow field and thus to a deficient removal of process by-products. The suction nozzle also has an influence on the flow field of the protective gas. Known geometries of suction nozzles can lead to non-uniform flow rates over the nozzle width. In addition, the flow rate at the suction nozzle is markedly slower in known devices than the flow rate directly after the inlet nozzle. This latter fact is the reason why, in known devices, the sum of the fluid-dynamically relevant cross-sectional areas at the entrances of suction nozzles, that is, the orifices of suction nozzles, is at least three times as large as the sum of the fluid-dynamically relevant cross-sectional areas at the exits or inlet orifices of the upper and lower inlet nozzles. Because, on account of the volume flow and the cross sections of the inlet and suction nozzles, a subsonic flow and thus incompressible flows may be assumed to occur, the ratio of the flow rates at the inlet and outlet nozzles is obtained via the ratios of the mentioned fluid-dynamically relevant cross-sectional areas. The mentioned low flow rates as well as the overall inhomogeneous flow field within the construction spaces of known devices lead to a deficient removal of process by-products. Thus, in known devices for selective laser beam melting, flaws in the process and in the component increasingly occur in certain construction space regions, so that these regions are not suitable for the production of serially manufactured components. These flaws occur, in particular, owing to the mentioned deficient removal of process by-products. The process by-products in selective laser-beam melting can be, in particular, smolder (welding fumes), spatter, ejected material, and dispersed powder. Smolder, in particular, leads to defocusing and shielding of the laser beam. As a result, the energy density that needs to be introduced onto the melting material drops and the powder is melted only deficiently. This leads to deficient bonding to the component, as a result of which, in turn, bonding flaws can occur in the component. In addition, spatter and ejected material lead to a marked local increase in the layer thickness. As a result, in turn, a deficient bonding to the component and bonding flaws can occur.